1. Field of the Invention
This invention relates to a printing system constituted by a printing apparatus for printing out print data and an information processing apparatus connected to the printing apparatus for transferring print data to the printing apparatus, a printing control apparatus and method used to control this printing system, a printer driver and a storage medium for storing the printer driver.
2. Description of the Related Art
In a printing system constituted by a printer and a host such as a personal computer, the personal computer generally creates print data and transfers the print data to the printer. Whenever the printer receives the print data from the personal computer, the printer develops the print data into image data at the set resolution and number of tonality levels and then prints out the image data.
The printer used in this printing system has a function for automatically executing resolution/tonality modification processing, which is processing for changing the resolution and/or number of tones, set for the print data, to a lower resolution or smaller number of tones (grays) in dependence upon control conditions that include the storage capacity that can be utilized to develop the print data into the image data and the utilizable printout speed. More specifically, if the set resolution is high and the number of tones is large, the storage capacity required is large and developing the image data takes time. Accordingly, on the basis of control conditions inclusive of the storage capacity usable for image development processing and the printing speed of the printer, the printer determines, whenever it receives print data, whether the image data can be developed at the resolution and number of tones that have been set for the print data. If the image data cannot be developed, the printer judges that it is necessary to execute resolution/tonality modification processing to change the resolution and number of tones to a lower resolution and number of tones. In such case the printer invalidates the processing that was executed up to the moment the aforementioned determined was made and re-generates image data that conforms to the resolution and tonality obtained by reducing the resolution and number of tones of the print data received thus far. By implementing the resolution/tonality modification processing function when image data cannot be developed under the above-described control conditions, it is unnecessary to suspend printout for the purpose of resetting resolution and tonality.
When the resolution/tonality modification processing for changing the resolution and number of tones to a lower resolution and smaller number of tones is executed in the conventional printing system, image data conforming to the resolution and tonality obtained by reducing the resolution and number of tones of the print data received thus far is generated again, as set forth above. As a consequence, printing out the image data takes a longer period of time. The time needed for printout is greatly prolonged especially when printing out a plurality of pages.